1. Field of the Invention
The present invention relates to a vehicular collision detection apparatus that detects collision of a vehicle with an object.
2. Description of Related Art
Conventionally, apparatuses that detect collision of a vehicle with an object are described in, for example, JP-A-2005-538881 corresponding to US 2005/0116817 and JP-A-2006-117157 corresponding to US 2006/0087417. JP-A-2005-538881 describes a front sensor for a vehicle, which sensor has a sensing element in a cavity of the sensor. The front sensor uses the sensing element to detect the collision depending on deformation of the cavity. Also, JP-A-2006-117157 describes an apparatus that determines whether a collision object is a pedestrian based on change of pressure in the chamber space air-tightly formed within a bumper cover.
In a case where a chamber forming member (chamber space) of the above collision detection apparatus may not be substantially air-tightly formed or may not be substantially sealingly provided, for example, when the chamber forming member is damaged, such as formation of a large hole thereon, pressure in the chamber may not substantially change disadvantageously even when a pedestrian collides with the vehicle. Thus, in a case where the chamber space is not substantially air-tightly formed, there is needed to detect that the collision detection apparatus is operated under an abnormal condition.